Xylem tissue. Light micrograph (LM) of a section through sunflower(helianthus annuus) tissue showing spiral tracheids, a type of xylem. Tracheids are long tubular cells with lignin, a material that provides support, in the cell walls. Spiral thickening of the cells can be seen. Tracheids conduct water from the roots of a plant along the stems to the leaves. Magnification: x210 when printed 10cm wide.